Investigation of Mg modified mesoporous silicas and their CO2 adsorption capacities

► Dispersion, co-condensation and ionic exchange methods were adopted to impregnate Mg. ► Highly dispersed state of MgO is the key point to improve CO2 adsorption capacity. ► Amine modification can provide the ligand for Mg2+ to increase MgO dispersion state. ► Al3+ can attract Mg2+ dispersed in channels to improve CO2 adsorption synergistically.